Make all container types pointers

Array and VLA were not pointers in `struct side_type' like other
container types such as struct and variant. Make those pointers to
ensure container types are all similar.

API change (user-visible): This prevents defining array and VLA fields
inline. That is, it is now necessary to define the array/VLA type
before referencing it in a field.

Change-Id: Ia3634a40514d827cb23ce242fb6bd05c7c583e34
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add optional type

The `SIDE_TYPE_OPTIONAL' denotes a field that can be absent from the
trace.  Such field has no attribute.  Instead, the optional type is
simply a pointer to another type.

The determination of absence for an optional field is determined by the
`selector' member of the `side_arg_optional' structure, which must be
the constant value `SIDE_OPTIONAL_ENABLED' if the field is present,
otherwise `SIDE_OPTION_DISABLED'.

Change-Id: Ie23bcac27efef66938981d59b715a950465ede75
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add test cxx to gitignore

Change-Id: I09ddf58825a2467bfac0f7bf715ffa3738818cc8
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add contextual description on failed runtime check

The following is an example of error output emitted before aborting:

================================================================================
                                 ERROR!
Type mismatch between description and arguments
Expecting `SIDE_TYPE_U32' but got `SIDE_TYPE_U64' in:

myprovider:myevent
        field: "abc"
================================================================================
Aborted

Change-Id: I695cafe59a92970f7c51ec894eb02fc0008c1c64
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add C++ unit test

Change-Id: I79e850e40b4e7d97f859b7ada8f1f6708ca3395f
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Support Clang

Most of the warnings emitted where due to either gcc extension or C99
extension used in C++.  Turn-off these warnings by using _Pragma.

Change-Id: I0421d888154df1a98543cc0c0fb7e4b448d25da1
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce dynamic compound literal

In C++, compound literal are temporary objects which have a lifetime
bound to its expression.  To extend the lifetime of such objects, the
`SIDE_DYNAMIC_COMPOUND_LITERAL' macro is introduced.

In C, this macro expands to `SIDE_COMPOUND_LITERAL'.  In C++, it
allocates the necessary size to store the object onto the stack using
`alloca(3)'.  The memory is then initialized by copying the expression
to it.

This is necessary for attributes of dynamic fields.  However,
`SIDE_DYNAMIC_COMPOUND_LITERAL' only return a pointer to the object and
not its size.  To overcome this, the API is changed and the
`side_dynamic_attr_list()' macro must be used on dynamic arguments of
dynamic fields.  The macro itself is not defined by libside.  Instead,
macro dispatching is done to get the pointer to the object and its size.

Change-Id: Ieddaa6b2209c03031cef916033efd57564229db5
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Make it compatible with C++

The main change are for initialization order of compound literal.  Other
changes include:

  - Initialization of zero size member (char end [0]),

  - Declaration of events in anonymous namespace for circular dependency
    of static variables.

Change-Id: Icb99c22a7df313ecb0e31a8d96ea6e9ec00cffed
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add C native types macro helpers

The SIDE ABI specifies fixed sizes integers and floating points.
However, as a convenience for C/C++, the SIDE C API supports C native
types (e.g. char) which are translated to their equivalent.

Note that the translation of C native types is toolchain dependent and
therefore could produce different results.

The main use case is for auto-generating SIDE events for public API of
shared libraries.

Change-Id: I845f0dd42ba2dc2de1f540f751e9cd65aa4a8c98
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Replace side_event_cond by side_event_enabled

This will allow users to test for side_event_enabled in scenario where
they wish to early return rather than conditionally do something.

Change-Id: I054f8087afaf40447949a1fbab37bef2c343da19
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing public header files for installation

Change-Id: Idc490bb09826d999f49d2cfdb9111df67b3c2d3a
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove specification draft

The SIDE specification is moved to https://git.efficios.com/side-spec.git

Change-Id: I65b14b0b3a87bcd246d91f701aa63a25ea324ce5
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename RFC document to SIDE-SPECRC-1.0.md

Change-Id: Ie0b78aa30d62ffa442eabd313f4d0087403f1a74
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update side spec

Change-Id: Iecf9193956440888b7f71f508ba4ade6113fe8a8
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add missing license and copyright headers

Also convert rfc-side-abi.txt to markdown, it was already almost valid
and allows licensing comments.

Change-Id: Ide55ddda455c20509c4b02258f93eef7daf434e9
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update autotools archive macros

Change-Id: Id845d45a0bd13e504a250db3720e6259ac513d68
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add git-review config

Add .gitreview for contributors wishing to use gerrit for patch
reviews.

Change-Id: I1eb09fe09c54100100c99f893f775c7d26229686
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add key characteristics to rfc

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Clarify TODO for user events integration

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove enum before/after for description visitor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove enum before/after for arg vec visitor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce event/type description visitor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

pretty print tracer: Use argument vector visitor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce argument vector visitor

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

pretty print: do not print 2 levels of brackets for variant

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

pretty print tracer: use { } for structures and fields

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

pretty print tracer: add missing comma in caller printout

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

pretty-print tracer: cleanup dynamic {} and remove caller addr

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: tracer: utf16/32 gather types handling

tracer_convert_string_to_utf8 should return the size of the input
(including null terminator) rather than the size of the utf8 output.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update rfc

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename rfc-libside.txt to rfc-side-abi.txt

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update libside RFC

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update libside rfc

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add libside RFC

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: handle EINTR correctly in get_cpu_mask_from_sysfs

If the read() in get_cpu_mask_from_sysfs() fails with EINTR, the code is
supposed to retry, but the while loop condition has (bytes_read > 0),
which is false when read() fails with EINTR. The result is that the code
exits the loop, having only read part of the string.

Use (bytes_read != 0) in the while loop condition instead, since the
(bytes_read < 0) case is already handled in the loop.

Original fix in liburcu from Benjamin Marzinski <bmarzins@redhat.com>:

  commit 9922f33e2986 ("fix: handle EINTR correctly in get_cpu_mask_from_sysfs")

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

side: Introduce caller address

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

side: explicit statedump request key

Make the statedump request key explicit rather than hiding it as a
Thread-Local Storage variable within libside. It's type is still opaque
to the application (void *), but this allows schemes where the statedump
callbacks are not required to emit statedump events from the same
thread: it can pass the statedump_request_key to another thread
responsible for emitting those events.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

rcu: Update following librseq public API updates

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup function argument alignment

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement side_cpu_relax for x86

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document application fork/clone vs statedump locking limitations

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Handle statedump agent thread state across fork

Implement pthread_atfork handlers to deal with statedump agent thread
state across fork.

For glibc, this requires glibc 2.24 or more recent.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement agent thread wakeup scheme with pthread cond var

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement agent thread

Currently uses 1 second polling for state. To be replaced by a proper
wait/wakeup.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

list: fix safe list iteration

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Statedump improvements

- Introduce polling vs agent thread statedump callbacks,
- Use uint64_t for tracer key.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Extend statedump API

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce side ptrace hook

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use RCU for statedump

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add rculist

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce list_types.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement statedump unit test

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement statedump request notifications

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use TLS variable for key state

Keep this hidden from the application.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add "key" to callback registration

This is in preparation to support the state-dump feature.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update gitignore

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove backup file

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add indirection for visitor arguments

In order to keep the argument vector const, add an indirection for
visitor arguments to a non-const area of memory, which is clearly
documented as modified by libside.

Add a "cached_arg" placeholder pointer to the visitor structures.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement 128-bit integer support

TODO in tracer example: Implement 128-bit integer with len_bits != 128
or nonzero offset_bit.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

API: Add 128-bit integer support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add __int128 support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Integer 128 split byte order helpers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Revert "Remove const on all side_arg"

This reverts commit 511ee756cf8aa9259489b4386feb2911bb58c20a.

Re-introduce constness of side_arg to ensure that side_calls are pure.

This will facilitate integration with various runtimes and eliminate
corner-cases.

We plan on copying side argument vectors within libside when translating
from visitor types to flattened types.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use zero-sized array as last field of event description

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add u128/s128 integer to ABI

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

API: Intitialize arg flags to 0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

ABI: Introduce incomplete type flag

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove const on all side_arg

Remove const from side_arg and types containing a side_arg so they can
be altered by libside for visitor caching.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove packed from visitor ABI

The visitor ABI is a contract between instrumented applications and
userspace tracers only, and follows C calling convention, so packing
those data structures serve no purpose.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move side_callback to libside internals

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove packed from struct side_callback

This is internal to libside.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename side state "p" field to "parent"

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move nr_callbacks to event state

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use uintptr_t for enabled state to eliminate partial register stalls

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

side event state does not need side_ptr_t

This is not relevant for tracers: only between instrumented application
and libside.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove event state abi version validation from tracer

This is internal to libside.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document ABI extensibility schemes

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move ABI headers under side/abi/

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove unneeded fwd declaration

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Split trace.h into API/ABI sub-headers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce event state ABI version

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Extensible struct side_event_state

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document side_ptr_get can be used as r or lvalue

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update side_ptr_t macros

Allow fetching a single 32-bit pointer on 32-bit architectures.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use structure size and version for event description extensibility

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update gitignore to ignore editor .swp files

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove bogus swap file

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

tracer: Validate number of known event types

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add nr_side_type_label and nr_side_attr_type event description fields

Allow tracers to discover whether they know about all field types
present when the event instrumentation was compiled.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

enum side_error is actually used

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Enforce ABI size checks

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

side.c: Use assert to validate flags

Flag validation is redundant with the logic already verified on
registration. Therefore, use an assertion, which can be compiled-out
when performance matters.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Cleanup: Add missing () around macro parameter

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use event state as argument to call fast path

Eliminate the need to load the event description cache lines (to load a
pointer to the event state) on the fast path by passing a pointer to the
event state as argument to the call.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Move back nr_callbacks to event description

nr_callbacks is not used on the fast path, therefore move it back to the
event description to optimize cache density of the event state enabled
flags.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Use side_enum_t for enum side_type_label_byte_order

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Comment that side_error enum is unused

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Use side_enum_t for side_loglevel enum

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Use side_enum_t for side_attr_type enum

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

trace.h: Use side_enum_t for enum side_type_label

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>